Mixcraft relies upon Microsoft DirectShow, along with any DirectShow-compatible video codecs that you have installed on your computer. What happens when you try to import the MP4 file? Is there an error message? If so, what does it say?

Mixcraft relies upon Microsoft DirectShow, along with any DirectShow-compatible video codecs that you have installed on your computer. What happens when you try to import the MP4 file? Is there an error message? If so, what does it say?

MP4 (MPEG4) is a wrapper. What MX deals with is the actual codec inside the wrapper (such as H.264), and that's often hard to determine unless you use a tool like GSpot. It's not uncommon to have some MP4 files that play great and some that won't play at all.

If this sounds utterly confusing, it is and has been for a long time through no fault of MX.